The present invention relates to a material transport device that supplies blank material to a transfer press machine. Described in more detail, the present invention relates to a material transport device that supplies blank material that sags easily because of its large size.
Material supply devices for supplying blank material from a destack device to a transfer press are disclosed in the prior art. Japanese Patent Publication Number 3010401 discloses an intermediate transport device, wherein: a blank material loaded on a destack device is passed from an attaching piece to a lower surface of a first magnet conveyor. Next, the material is passed to an upper surface of a second magnet conveyor and is transported to a final stage. At the final stage, because of the rising of a chute, the blank material is separated from the second magnet conveyor. Finally, a feed bar of the transfer press clasps the blank material from the chute and transports it to the first stage of the press.
In recent years, people in the press working industry have been studying how to use a single transfer press to process large blank materials or sheet materials (for example, having a front-back dimension of 1300 mm or greater) that have previously been processed by a press line (a so-called tandem line) in which loaders and unloaders are stationed between a plurality of presses. This has become realizable due to the improvement in die technology. By conducting production with a single transfer press, advantages over the tandem line, such as space conservation, improved production speed, and the like, are anticipated.
With a material transport device of the prior art as disclosed in the previously described Patent Publication Number 3010401, the large blank material or sheet material that is loaded on a destack device can be transported to the final stage. The blank material is transported from the final stage to the first stage of the press, where processing is begun, by clasping the edges of the blank material with feed bar fingers. Such edge support of a blank material that is large and has a weak middle, permits the center part of the blank material to sag, thus making transport difficult. In order to solve this problem, clip fingers and the like have been tried, but an adequate transport capability has not been achieved.
The object of the present invention is to provide a material transport device that reliably transports large blank materials and sheet materials to the first stage of a press without permitting the material to sag.
The invention described is a material transport device, comprising: a guide body that can be raised and lowered; a plurality of shuttle bars that move in a feed direction by being guided by the guide body and that are provided between a plurality of magnet belts which transport the blank material to a final stage; and an attachment member that is provided on a lower surface of the shuttle bar and attaches and retains the blank material. By lowering the shuttle bar and the attachment member together with the guide body, the blank material that is attached to a lower surface of the magnet belt is separated from the magnet belt. The attachment member attaches and retains the blank material. By moving the attachment member together with the shuttle bar to a first stage, the blank material is transported to the press machine.
According to the invention, the blank material, which has been transported to the final stage attached to the lower surface of the magnet belt, is separated from the magnet belt by the attachment member that descends from above the blank material. In addition, the blank material is attached and retained by the attachment member. Because the attachment member and the shuttle bar move together, the blank material is. transported to the first stage while the blank material is being attached and retained by the attachment member. The blank material is then released at the first stage.
For the transport from the final stage to the first stage, the blank material is attached and retained by a plurality of attachment members. In other words, with blank materials that are large and have a weak middle, because they are retained at a plurality of points, the sagging of the center portion that occurs when the edges are clasped by fingers is avoided, and the blank material is reliably transported to the first stage.
The blank material is processed at the first stage so that it has a higher form rigidity. As a result, the blank material can be transported to the next step by clasping the edges with feed bar fingers. In other words, transport from the first stage and beyond is reliably conducted with feed bars.
With the present invention, even a large blank material with a weak middle is reliably transported from the final stage to the first stage. As a result, the processing of a large blank material (sheet material) that had been processed by a tandem line in the prior art is processed by a transfer press.
Furthermore, when the present invention is used in a system in which the central feed bar is removed together with the moving bolster during die exchanges, the left-right dimension of the press is reduced by an equivalent of one stage compared to the standard press. In other words, usually, the length of the feed bar must be enough to reach the final stage. However, with the present invention, the material is transported to the first stage, and the central feed bar needs only to be long enough to reach this first stage. If the center feed bar is shortened by the length of one stage, the dimension between the left and right columns is also shortened. This results in large cost savings, and the rigidity of the press is improved.
Furthermore, because the final stage does not require a chute as in the transport device of the prior art, a space is formed below the final stage. An oil coating device, for example, may be placed in this space. This is advantageous when oil is coated on both sides of a blank material as when molding a high tension steel plate.
In addition, the invention is a material transport device as described above, wherein the attachment member is formed by a magnet.
Furthermore, the invention is a material transport device as described above wherein the attachment member is formed by a vacuum cup.
According to the invention, in addition to the advantages of the invention described above, by forming the attachment member from a magnet, the attachment member is inexpensive. In addition, according to the invention, in addition to the advantages of the invention described above, by forming the attachment member from a vacuum cup, transport is reliably conducted even when transporting large blank materials that are not magnetic.